Speed responsive switch



y 3, 1963 H. G. ADLER 3,098,394

SPEED RESPONSIVE SWITCH Original Filed Jan. 15, 1958 v 2 Sheets-Sheet 1 FIG.I.

jl- I40 bra J f ATTORNEYS July 23, 1963 H. s. ADLER SPEED RESPONSIVE SWITCH Original Filed Jan. 15, 1958 2 Sheets-Sheet 2 INVENTOR. ADLER ATTORNEYS United States Patent Oflice 3,098,394 Patented July 23, 1963 Claims. c1. 73 ss1 The present invention relates to a speed responsive switch. The present application is a division of my prior co-pending application Ser. No. 709,089, filed January 15, 1958.

It is an object of the present invention to provide a switch adapted to be closed upon attainment of a predetermined speed of a rotary element, to include means for adjusting the switch to provide for switch actuation at different speeds and to provide means which permit attainment of speeds in excess of the speed required to actuate the switch by the rotary element without damage to the switch.

More particularly, it is an object of the present invention to provide an adjustable speed responsive switch adapted particularly for connection to a part of a motor vehicle which rotates at a speed determined by engine speed or road speed such, for example, as the generator.

It is a further object of the present invention to provide a switch of the character described including remotely positioned means for adjusting the speed setting to which the signal is to operate.

It is a further object of the present invention to provide a speed setting device for a speed responsive switch which is capable of producing extremely fine and accurate adjustment of the speed setting.

Other objects and features of the invention will become apparent as the description proceeds especially when taken in connection with the accompanying drawing illustrating a preferred embodiment of the invention wherein:

FIGURE 1 is a fragmentary side elevation of the speed responsive switch and the means for adjusting the speed setting.

FIGURE 2 is a sectional view through the speed responsive component of the switch.

FIGURE 3 is an end view of the structure shown in FIGURE 1.

FIGURE 4 is a sectional View on the line 4-4 of FIGURE 1.

FIGURE 5 is an exploded view of the separate workable components of the speed adjuster.

The speed responsive switch is adapted to control a pair of relatively movable switch contacts in accord with the speed of a rotating element. Accordingly, it may be used in any construction in which a signal or control is desired which is variable in acccord with engine speed. In the particular embodiment of the invention illustrated herein, switch contacts are shown as normally open but it will, of course, be appreciated that normally closed contacts may be provided which are adapted to open at a predetermined speed and alternately relative movement between elements of the switch may be connected if desired to actuate a series of switch contacts in sequence.

Referring to FIGURES 1 and 2, it will be observed that the speed responsive switch includes an adjustable but normally stationary contact 20 and a movable contact 26 which is movable axially of an actuating shaft such as, for example, the shaft of a generator. This speed responsive switch comprises a nut 66 adapted to be screwed onto the threaded shaft of the generator 28 and to be located thereon by a lock screw 63 received in a threaded opening 70 provided in the nut 66. Fixed to the nut is an inner housing portion 72 having a reversely turned flange 74 at its outer edge engaging a complementary housing portion 76 which is provided with an elongated tubular flange portion 78. Received between the flange portion 78 and the elongated cylindrical contact member 26 is a bearing 80 to provide for rotation of the housing while the contact member 26 is prevented from rotation.-

In order to prevent rotation of the contact member '26, its end portion which projects beyond the outer end of the tubular flange 78 is provided with a transverse opening 84 adapted to receive a wire to prevent its rotation.

Fixed within the housing member 72 is a hardened plate constituting an inner ball race 86. Conveniently, the plate 86 may be staked or otherwise fixedly attached to the housing member 72 to prevent relative rotation therebetween.

The forward end of the nut 66 is reduced as indicated at 90 and rotatable on this reduced end portion is a member 92 having generally radially extending slots in which are received the balls 94 which are the centrifugal elements of the switch. A snap ring 95 is received in a groove adjacent the end of the reduced portion 90 of the nut to retain the member 9-2 thereon. Since the driver is rotatable on the nut 66, a thin laterally distorted friction washer 95a is provided intermediate the snap ring and the hub portion of the member 92. The friction washer transmits a light frictional pressure to the member 92 to initiate rotation.

Fixedly carried on the inner cylindrical portion of the contact member 26 is an outer ball race. 96 which includes a conically inclined portion 98 engaged by the balls 94 so that radial outward movement of the ball in response to centrifugal forces developed by rotation of the nut 66 effects axial movement of the outer race '96.

Mounted on the inner cylindrical portion of the contact member 26 is a bearing plate 100 and between this hearing plate and the outer flat surface of the ball race 96 are a plurality of bearings 102. Interposed between the bearing plate 100 and a seat 104 formed at the interior of the housing member 76 is a relatively strong compression spring 106 which opposes movement of the movable ball race 98 in response to centrifugal forces.

From the foregoing, it will be apparent that to any particular speed, which is represented by a corresponding thrust on the movable ball race 98 resulting from centrifugal forces acting on the balls, a position of balance is achieved in which this force is balanced by the compression spring 106. Accordingly, at any particular engine speed, the contact element will have a corresponding position and will move axially in or out of the housing upon decrease or increase in engine speed.

Referring now more particularly to FIGURES 1, 3, and 5, there is illustrated the mechanism for effecting accurate adjustment for the speed responsive switch. The adjusting mechanism is mounted on a threaded stud 110 which extends through a bracket 112 provided on the side of the generator 28 for the purpose of adjusting the generator relative to a slotted bracket 114 to maintain belt tension. Mounted on the stud 110- is a clamp 1116, details of which are best seen in FIGURE 4. The clamp includes two complementary clamping elements 117 and 118 having portions shaped to grip the stud 110 and additional shaped portions to grip the flexible armored cable of a Bowden wire 120.

Clamped to the stud 110 adjacent its outer end is a mounting bracket 122. Clamping is effected by the clamp 124 engaged by fastening elements 126 to the bracket 122 at opposite sides of the stud 110. At a position remote from the stud 110 the bracket 122 has a turned-up ear 128 provided with a threaded opening 130 for receiving an adjustable abutment screw 132 and a second opening 134 for receiving a tension spring 136.

" As best seen in FIGURE 5, the bracket 122 is also provided with a pivot pin 138 having a reduced downwardly extending portion 140 extending through an opening in the bracket and adapted to receive the eye 142 of a wire 144 the other end of which extends through the opening 84 in the end portion of the contact member 26. The pin 138 is riveted in position, a washer 146 being provided outwardly beyond the eye 142 of the wire 144.

Mounted on the pivot pin 138 is an adjusting lever 148 having an opening 150 in which the pivot pin 138 is received, the opening 150 being provided eccentrically in a cylindrical stud 152. The adjusting lever 148 at its opposite end carries a pin 154 to which is pivoted a connector block 156 clamped as by a screw 158 to the outer end of the inner Wire 160 of the Bowden wire 120. Since the armored cable or housing of the Bowden wire is clamped by the clamp 116, movement of the adjusting wire 160 effects swinging movement of the adjusting lever 148 and it is contemplated that the adjusting lever may have approximately 90 degrees of arcuate movement as indicated by the positions of these levers shown in dotted lines at 148a and 148b.

A contact arm 162 has an enlargement 164 at one end provided with a cylindrical opening 166 dimensioned to fit over the stud 152 carried by the adjusting lever 148. The contact arm 162 is retained in position on the stud 152 and the adjusting lever 148 is retained in position on the pivot pin 138 by a washer 168 engaged by a releaseable spring clip 170 received in an annular groove 177 at the outer end of the pivot pin 138. At the outer end of the contact arm 162 there is provided the contact element 20 previously referred to which is secured thereto by a screw 174. Contact element 20 is in electrical connection with an electrical conductor 20a.

The contact arm 162 is provided with a pin 176 which engages the other end of the tension spring 136. Accordingly, as best seen in FIGURE 1, the spring 136 urges the contact arm 162 in a counterclockwise direction about the axis of stud 152 to a position in which its edge engages the end of the adjustable abutment screw 132. This positions the contact element 20 at a predetermined distance from the outer end of the movable contact 26 when the centrifugal device is not turning. Accordingly, it determines the speed at which the centrifugal device must rotate to move the movable contact member 26 outwardly into contact with the adjustable contact 20.

Movement of the adjusting lever 148 about the axis of pin 138 results in movement of the end of the contact arm 162 which receives the eccentric boss 152 of the adjusting lever 148. The amount of eccentricity between the inner surface 150 and the outer cylindrical surface of the stud 152 may be relatively small so that the speed adjustment is not at all sensitive. As a corollary to this, the speed may be set with very considerable accuracy.

From the foregoing, it will be observed that a very simple speed responsive switch has been provided which may be quickly and easily attached to existing components of an engine if desired. The speed responsive switch, of course, is capable of use in conjunction with any device which includes a rotary element to which the nut 66 may be secured.

It will be recalled that the race 96 is fixed to the elongated contact element 26 and is accordingly prevented from rotation by the wire 144. The slotted member 92 is rotatable on the reduced end portion 90 of the nut 66. Accordingly, the balls 94 receive the driving impulse from the positively driven raceway 86. Since this driving impulse is applied to the periphery of the balls, the balls are driven in rotation as well as revolved about the axis of the shaft, and the speed to which the balls revolve about the axis of the shaft is accordingly approximately one-half of the shaft speed. The device, therefore, operates as a self-contained speed reducer and permits the use of rigid and more efiicient operating balls than would otherwise be the case.

A second advantage of the arrangement in which the balls are driven in rotation on the surfaces of the driving race 86 and the nonrotating race 96 is that the balls are maintained in constant rotation about an inclined axis and hence there is no radial inertia to be overcome upon a change in speed. Consequently, the balls respond instantaneously to extremely small changes in shaft speeds, substantially eliminating hysteresis.

The drawings and the foregoing specification constitute a description of the improved speed responsive switch in such full, clear, concise, and executed details as to enable any person skilled in the art to practice the invention, the scope of which is given by the applicants claims.

What I claim as my invention is:

1. A speed responsive device comprising (a) a rotary drive member,

(b) a first annular ball race fixed to said drive memher for rotation therewith,

(c) a second annular ball race disposed in axial alignment with said first race and spaced transversely therefrom,

(d) means mounting said second race for movement toward and away from said first race and for preventing rotation of said second race,

(e) one of said races having a planar surface extending normal to the axis of rotation of said first race and the other of said races having a dished surface spaced from and in axial alignment with said planar surface,

(f) an annular spacer mounted for rotation independently of said drive member and disposed intermediate said races,

(g) said spacer having generally radially extending slots,

(/1) balls disposed in said slots and engaged at opposite sides by said surfaces of said races, and

(i) resilient means operatively connected to said race to oppose movement thereof in a direction away from said first race.

2. A speed responsive device comprising (a) a rotatable housing having an end wall,

(b) a first ball race in said housing and fixed thereto,

(c) said first race having a planar surface,

(11) a radially slotted ball separator independently rotatably mounted in said housing,

(e) balls disposed in the slots of said separator and rotatably driven by said planar surface of said first ball race,

(f) an elongated shaft extending through an opening into said housing,

(g) means exterior of said housing engaging said shaft to prevent rotation thereof,

(12) a second ball race fixed on said shaft and having a dished surface engaging said balls,

(i) a thrust bearing fixed on said shaft between said end Wall and said second race, and

(j) a spring in said housing operatively connected to said shaft to oppose axial movement thereof.

3. A device as defined in claim 2 in which said spring extends between said end Wall of said housing and said bearing.

4. A speed responsive device for connection to the end of a drive shaft,

(a) a housing fixed to one end of said drive shaft, for

rotation therewith,

(b) a first ball race fixed within said housing for rotation therewith and having a planar surface disposed in a plane extending normal to the axis of said shaft,

(0) a stub shaft parallel to said drive shaft and extending through an opening in said housing,

(d) means exterior of said housing engaging said stub shaft to prevent rotation and accommodate axial movement thereof,

(e) a second ball race fixed to said stub shaft within said housing and having a dished surface facing the planar surface of said first race,

(1'') a plurality of annuiarly spaced balls engaged between said race surfaces and rotatably driven by sm'd first race,

(g) a spring in said housing between a wall of said housing and said second race,

([1) a thrust beaming between one end of said spring and said second race and (i) a radially slotted member disposed in said housing intermediate said races and receiving said balls in its slot,

(j) said slotted member being rotatable on said drive shaft axis independently of the rotation of said drive shaft and said housing.

5. A speed responsive device for connection to the end of a drive shaft, a housing fixed to one end of said shaft, a first ball race fixed within said housing and having a planar surface disposed in a plane extending normal to the axis of said shaft, a stub shaft parallel to said drive shaft and extending through an opening in said housing, means exterior of said housing engaging said stub shaft to prevent rotation and accommodate axial movement thereof, a second ball race fixed to said stub shaft within said housing and having a dished surface facing the planar surface of the first mace, annularly spaced balls engaged between said race surfaces and rotatably driven by said first race and said second race, a thrust bearing between one end of said spring and said second race, a radially slotted member disposed in said housing intemnediate said races and receiving said balls in its slots, said slotted member being rotatable on said drive shaft axis independently of rotation of said housing, and means fnictionally drivingly coupling said slotted member to said drive shaft only on initial low speed rotation thereof.

References Cited in the file of this patent UNITED STATES PATENTS 1,241,808 Balough Oct. 2, 1917 2,319,654 Adler May 18, 1943 2,598,481 Young May 27, 1952 2,603,472 Adler July 15, 1952 2,836,670 Laas May 27, 1958 2,856,479 Fletcher Oct. 14, 1958 2,968,961 Gauthier Jan. 24, 1961 FOREIGN PATENTS 567,423 Canada Dec. 16, 1968 2,628 Great Britain Dec. 5, 1896 

1. A SPEED RESPONSIVE DEVICE COMPRISING (A) A ROTARY DRIVE MEMBER, (B) A FIRST ANNULAR BALL RACE FIXED TO SAID DRIVE MEMBER FOR ROTATION THEREWITH, (C) A SECOND ANNULAR BALL RACE DISPOSED IN AXIAL ALIGNMENT WITH SAID FIRST RACE AND SPACED TRANSVERSELY THEREFROM, (D) MEANS MOUNTING SAID SECOND RACE FOR MOVEMENT TOWARD AND AWAY FROM SAID FIRST RACE AND FOR PREVENTING ROTATION OF SAID SECOND RACE, (E) ONE OF SAID RACES HAVING A PLANAR SURFACE EXTENDING NORMAL TO THE AXIS OF ROTATION OF SAID FIRST RACE AND THE OTHER OF SAID RACES HAVING A DISHED SURFACE SPACED FROM AND IN AXIAL ALIGNMENT WITH SAID PLANAR SURFACE, (F) AN ANNULAR SPACER MOUNTED FOR ROTATION INDEPENDENTLY OF SAID DRIVE MEMBER AND DISPOSED INTERMEDIATE SAID RACES, (G) SAID SPACER HAVING GENERALLY RADIALLY EXTENDING SLOTS, (H) BALLS DISPOSED IN SAID SLOTS AND ENGAGED AT OPPOSITE SIDES OF SAID SURFACES OF SAID RACES, AND (I) RESILIENT MEANS OPERATIVELY CONNECTED TO SAID RACE TO OPPOSE MOVEMENT THEREOF IN A DIRECTION AWAY FROM SAID FIRST RACE. 